Rotavirus (RV) infections affect young children, but can also occur in adults. We sought to identify risk factors for RV infections in adults aged ⩾18 years in Denmark, and to describe illness and genotyping characteristics. From March 2005 to February 2009, we recruited consecutive cases of laboratory-confirmed RV infection and compared them with healthy controls matched by age, gender and municipality of residence. We collected information on illness characteristics and exposures using postal questionnaires. We calculated univariable and multivariable matched odds ratios (mOR) with conditional logistic regression. The study comprised 65 cases and 246 controls. Illness exceeded 10 days in 31% of cases; 22% were hospitalized. Cases were more likely than controls to suffer serious underlying health conditions [mOR 5·6, 95% confidence interval (CI) 1·7–18], and to report having had close contact with persons with gastrointestinal symptoms (mOR 9·4, 95% CI 3·6–24), in particular young children aged <3 years and adults aged >18 years. Close contact with young children or adults with gastrointestinal symptoms is the main risk factor for RV infection in adults in Denmark. RV vaccination assessments should consider that RV vaccination in children may indirectly reduce the burden of disease in adults.

This paper estimates the risk of bacterial meningitis following surgery between 1996 and 2009 in Denmark. We conducted two retrospective nationwide cohort studies; first by linking notified bacterial meningitis cases to the National Patient Registry to see how many had undergone a surgical procedure; second, we scrutinized notified bacterial meningitis cases to see if the clinician suspected a surgical procedure to be the aetiology. We found that ear, nose and throat surgery had an 11-fold, and neurosurgery a sevenfold, increased risk compared to the reference group in the first 10 days following surgery. Streptococcus pneumoniae was the pathogen most often involved. Operation procedures involving penetration of dura mater was associated with increased risk for post-operative bacterial meningitis. In absolute numbers we found few bacterial meningitis cases after surgery; however, patients undergoing certain surgical procedures are at-risk and should be considered when national vaccination guidelines are revised.

To identify determinants for mortality and sequelae and to analyse the spatial distribution of meningococcal disease, we linked four national Danish registries. In the period 1974–2007, 5924 cases of meningococcal disease were registered. Our analysis confirms known risk factors for a fatal meningococcal disease outcome, i.e. septicaemia and high age (>50 years). The overall case-fatality rate was 7·6%; two phenotypes were found to be associated with increased risk of death; C:2a:P1.2,5 and B:15:P1.7,16. B:15:P1.7,16 was also associated with excess risk of perceptive hearing loss. The incidence rates of meningococcal disease were comparable between densely and less densely populated areas, but patients living further from a hospital were at significantly higher risk of dying from the infection. To improve control of meningococcal disease, it is important to understand the epidemiology and pathogenicity of virulent ‘successful clones’, such as C:2a:P1.2,5 and B:15:P1.7,16, and, eventually, to develop vaccines against serogroup B.

We performed a systematic review to estimate the effectiveness of vaccination, in addition to chemoprophylaxis, in preventing meningococcal disease among household contacts. Medline, EMBASE, EMGM, and EUIBIS were used for data collection. Studies reporting on at least 100 primary cases and on subsequent cases in household settings with follow-up of more than 2 weeks after onset of disease in the primary case were reviewed. A meta-analysis was used to calculate the average attack rate in household contacts given chemoprophylaxis 14–365 days after onset of disease in the primary case. In total, 652 studies were identified, five studies and one unpublished report met the inclusion criteria. The weighted average attack rate was 1·1/1000 household contacts (95% CI 0·7–1·7). This review supports vaccination of household contacts in addition to chemoprophylaxis to reduce the risk of meningococcal disease among household contacts of a case caused by a vaccine-preventable serogroup.

Denmark has in the past 10 years experienced a decrease in the number of notified cases of meningococcal disease. In 1994 the completeness of the Notification System for Meningococcal Disease (NSMD) was estimated as 96% (95% CI 93–98). To answer the question whether the observed decrease reflects a real decrease in the incidence; we estimated the completeness of the notification system in 2002. We estimated the completeness of registration by a capture–recapture analysis. As the first data source, we used the national NSMD, which is an integrated surveillance system between the Department of Epidemiology and the Neisseria Reference Laboratory. The second independent source was the National Patient Registry (NPR). In 2002, the completeness of the NSMD was estimated as 96% (95% CI 95–98) and for the NPR as 84% (95% CI 82–85). The ‘real’ incidence rate was 1·9/100 000 population, which compared to 4·4/100 000 population in 1994. We concluded that the observed decrease in incidence rate is real. The NSMD in Denmark functions well and captures almost all cases of meningococcal disease. The complete registration which includes a unique personal identification number serves as an outstanding source for nationwide registry linkage studies.